I. Field of the Invention
This invention relates to a bone filler which is filled in a defect or a void of a bone.
II. Description of the Prior Art
A defect or a void may be formed in a bone due to, for example, a fracture or an operation for eliminating a bone tumor. Conventionally, to fill such a defect or void in the bone, autoplasty is conducted by filling with a bone material collected from another portion of the patient. In other cases, the bone material is collected from a near relative of the patient. However, in those methods, the bone material to be filled in the defect or void must be collected by conducting an operation from the patient or the near relative of the patient. Thus, the burden on the patient or the near relative of the patient is great. Further, when the defect or the void to be filled is large, it may be difficult to obtain sufficient bone material.
To overcome this problem, artificial bone fillers have been developed. The materials of the known bone fillers include metals and ceramics. Among these, from the view point of biocompatibility, calcium phosphate-based compounds are preferred. Among the calcium phosphate-based compounds, it is known that hydroxyl apatite which is a component of the bone is especially preferred. Conventional hydroxyl apatite bone fillers include those in the forms of granules, powder (Japanese Patent Disclosure (Kokai) No. 54841/81) or fibers (Japanese Patent Disclosure (Kokai) No. 7-117621). The bone filler in the form of granules or powder has the drawback that it is inconvenient to handle in an operation. As to the bone filler in the form of fibers, although the handling is easier than those in the form of granules or powder, the hydroxyl groups of the hydroxyl apatite are decomposed when the fibers are melt-spun, so that the biocompatibility is reduced.